Huge star explosions give clues to life’s origins

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The dynamics of the explosion that creates them causes some neutron stars to rotate rapidly – a fast as one hundredth of a second for a complete revolution.

By chance, Mezzacappa’s team came upon “the mechanism whereby these neutron stars may be spun up, and, therefore, the mechanism whereby pulsars may be born.  It was a secondary benefit to our research effort,” he says.  “We were trying to understand one phenomenon and in the process we came to understand a different one.”

Reviving the shock wave

Mezzacappa and his collaborators are working toward simulating a massive collapsing star with all the necessary physics in two dimensions.

“In doing so,” Mezzacappa says, “we will also advance the three-dimensional simulations that were used to discover the pulsar spin because those simulations had only a subset of the physics in them.”

Petaflops computing capability also could help researchers understand another key phenomenon: Why the shock wave propagating out from the collapsing core seems to stall.

“We know that it stalls because it loses energy as it plows through the star.  Eventually it loses enough energy to stall,” Mezzacappa says.  “The fundamental question in supernova theory, which is not yet answered, is how is the shock wave revived?”

Answering this and other complex questions relating to core-collapse supernovae events will lead to a more thorough understanding of how the elements of the periodic table are formed.  It’s an important concern of DOE’s nuclear physics program.

Core-collapse supernovae are the main source of elements in the periodic table between oxygen and iron.  It’s believed, but not known with certainty, that they also are responsible for half the elements heavier than iron.

“As such, these events would be the dominant source of elements in the periodic table, without which life as you and I know it – human life – would not exist,” Mezzacappa says.

“Many elements – the iron in your blood, the oxygen that you breathe, other metals that your body needs for its processes, even the gold in your wedding band – come from these core-collapse supernova events,” he adds.

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